ProtoChoice-P is a prospective multicenter trial to evaluate proton therapy in patients suffering from prostate cancer. Primary aim of the study is a decrease of moderate or severe genito-urinary or intestinal side effects (Common Terminology Criteria for Adverse Events (CTCAE) 4.0 grade 2 or higher) by the use of proton therapy. Secondary endpoints contain assessment of quality of life, biochemical recurrence and recurrence free survival as well as overall survival and economic comparison between photon and proton therapy.